Mashu

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  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 43.572°N
  • 144.561°E

  • 857 m
    2811 ft

  • 285081
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

The Global Volcanism Program has no activity reports for Mashu.

The Global Volcanism Program has no Weekly Reports available for Mashu.

The Global Volcanism Program has no Bulletin Reports available for Mashu.

Mashu is a 6-km-wide Holocene caldera that truncates a stratovolcano constructed on the ESE rim of the large Kutcharo caldera. The steep-walled caldera, filled by the remarkably transparent waters of Lake Mashu, is one of the scenic highlights of Hokkaido. Following caldera collapse about 7000 years ago, a small andesitic stratovolcano, Kamuinupuri, was formed beginning about 4000 years ago, creating a reentrant into the SE side of the deep caldera lake. A large explosive eruption about 1000 years ago, the latest dated eruption, created a 1.2 x 1.5 km crater at the summit of Kamuinupuri. The small island of Kamuishu in the center of Lake Mashu represents the tip of a mostly submerged dacitic lava dome.

Summary of Holocene eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
1080 ± 100 years Unknown Confirmed 5 Radiocarbon (corrected) Kamuinupuri, Tephra layer Ma-b
0350 ± 100 years Unknown Confirmed 2 Radiocarbon (corrected) Kamuinupuri, Tephra layer Ma-c1
0150 ± 100 years Unknown Confirmed 4 Radiocarbon (corrected) Kamuinupuri, Tephra layers Ma-c4-c2
2050 BCE ± 40 years Unknown Confirmed 4 Radiocarbon (corrected) Kamuinupuri, Tephra layer Ma-d
2800 BCE ± 750 years Unknown Confirmed 3 Tephrochronology Kamuinupuri, Tephra layer Ma-e'
3550 BCE ± 40 years Unknown Confirmed 4 Radiocarbon (corrected) Kamuinupuri, Tephra layer Ma-e
5550 BCE ± 100 years Unknown Confirmed 6 Radiocarbon (corrected) Tephra layers Ma-j-f

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.


Synonyms

Masyu

Cones

Feature Name Feature Type Elevation Latitude Longitude
Kamuinupuri
    Mashudake
Stratovolcano 857 m 43° 34' 20" N 144° 33' 39" E
Nishibetsu
    Nisibetu
Stratovolcano 800 m

Craters

Feature Name Feature Type Elevation Latitude Longitude
Mashu Caldera

Domes

Feature Name Feature Type Elevation Latitude Longitude
Kamuishu
    Kamuissyuto
    Kamuishuto
Dome 386 m
Kamuinupuri, its top in the clouds, is a small stratovolcano constructed on the SE rim of Mashu caldera. Growth of Kamuinupuri postdated the roughly 7000-year-old collapse of Mashu caldera. The steep scarp below the summit is the NE wall of a small, 1.2 x 1.5 km caldera that formed at the summit of Kamuinupuri about 1000 years ago, during the last eruption of Mashu volcano.

Photo by Lee Siebert, 1977 (Smithsonian Institution).
Mashu is a 6-km-wide caldera on the northernmost Japanese island of Hokkaido. It truncates a stratovolcano constructed on the ESE rim of the larger Kutcharo caldera. Mashu caldera is seen here from its SW rim with the small island of Kamuishi, a mostly submerged lava dome, in the center of the lake. The steep-walled caldera is one of the scenic highlights of Hokkaido. The latest eruption of Mashu took place about 1000 years from Kamuinupuri, whose lower flanks appear at the extreme right.

Photo by Lee Siebert, 1977 (Smithsonian Institution).
The deep blue waters of 6-km-wide Mashu caldera are seen here from its western rim. The small island of Kamuishu in the center of Lake Mashu (right-center) represents the tip of a mostly submerged lava dome. Mashu is a Holocene caldera that truncates a stratovolcano constructed on the ESE rim of the large Kutcharo caldera. Following caldera collapse, a small stratovolcano, Kamuinupuri (whose lower flanks are visible at the far right), was formed beginning about 4000 years ago.

Copyrighted photo by Shun Nakano, 2001 (Japanese Quaternary Volcanoes database, RIODB, http://riodb02.ibase.aist.go.jp/strata/VOL_JP/EN/index.htm and Geol Surv Japan, AIST, http://www.gsj.jp/).

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title.

IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior..

Japan Meteorological Agency, 1975. National Catalogue of the Active Volcanoes in Japan. Tokyo: Japan Meteorological Agency, 119 p (in Japanese).

Japan Meteorological Agency, 1996. National Catalogue of the Active Volcanoes in Japan (second edition). Tokyo: Japan Meteorological Agency, 502 p (in Japanese).

Japan Meteorological Agency, 2013. National Catalogue of the Active Volcanoes in Japan (fourth edition, English version). Japan Meteorological Agency.

Katsui Y, Ando S, Inaba K, 1975. Formation and magmatic evolution of Mashu volcano, east Hokkaido, Japan. Hokkaido Univ Fac Sci Jour, 16: 533-552.

Kishimoto H, Hasegawa T, Nakagawa M, Wada K, 2009. Tephrostratigraphy and eruption style of Mashu volcano, during the last 14,000 years, eastern Hokkaido, Japan. Bull Volc Soc Japan (Kazan), 54: 15-36 (in Japanese with English abs).

Kudo T, Hoshizumi H, 2006-. Catalog of eruptive events within the last 10,000 years in Japan, database of Japanese active volcanoes. Geol Surv Japan, AIST, http://riodb02.ibase.aist.go.jp/db099/eruption/index.html.

Nakano S, Yamamoto T, Iwaya T, Itoh J, Takada A, 2001-. Quaternary Volcanoes of Japan. Geol Surv Japan, AIST, http://www.aist.go.jp/RIODB/strata/VOL_JP/.

Volcano Types

Caldera
Stratovolcano
Lava dome

Tectonic Setting

Subduction zone
Continental crust (> 25 km)

Rock Types

Major
Andesite / Basaltic Andesite
Dacite
Basalt / Picro-Basalt

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
9,794
9,794
25,627
632,919

Affiliated Databases

Large Eruptions of Mashu Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).
WOVOdat WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.
EarthChem EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).
Smithsonian Collections Search the Smithsonian's NMNH Department of Mineral Sciences collections database. Go to the "Search Rocks and Ores" tab and use the Volcano Name drop-down to find samples.